Revision 9230a0b65b47fe6856c4468ec0175c4987e5bede authored by Dave Chinner on 20 November 2018, 06:50:08 UTC, committed by Darrick J. Wong on 21 November 2018, 18:10:53 UTC
Long saga. There have been days spent following this through dead end after dead end in multi-GB event traces. This morning, after writing a trace-cmd wrapper that enabled me to be more selective about XFS trace points, I discovered that I could get just enough essential tracepoints enabled that there was a 50:50 chance the fsx config would fail at ~115k ops. If it didn't fail at op 115547, I stopped fsx at op 115548 anyway. That gave me two traces - one where the problem manifested, and one where it didn't. After refining the traces to have the necessary information, I found that in the failing case there was a real extent in the COW fork compared to an unwritten extent in the working case. Walking back through the two traces to the point where the CWO fork extents actually diverged, I found that the bad case had an extra unwritten extent in it. This is likely because the bug it led me to had triggered multiple times in those 115k ops, leaving stray COW extents around. What I saw was a COW delalloc conversion to an unwritten extent (as they should always be through xfs_iomap_write_allocate()) resulted in a /written extent/: xfs_writepage: dev 259:0 ino 0x83 pgoff 0x17000 size 0x79a00 offset 0 length 0 xfs_iext_remove: dev 259:0 ino 0x83 state RC|LF|RF|COW cur 0xffff888247b899c0/2 offset 32 block 152 count 20 flag 1 caller xfs_bmap_add_extent_delay_real xfs_bmap_pre_update: dev 259:0 ino 0x83 state RC|LF|RF|COW cur 0xffff888247b899c0/1 offset 1 block 4503599627239429 count 31 flag 0 caller xfs_bmap_add_extent_delay_real xfs_bmap_post_update: dev 259:0 ino 0x83 state RC|LF|RF|COW cur 0xffff888247b899c0/1 offset 1 block 121 count 51 flag 0 caller xfs_bmap_add_ex Basically, Cow fork before: 0 1 32 52 +H+DDDDDDDDDDDD+UUUUUUUUUUU+ PREV RIGHT COW delalloc conversion allocates: 1 32 +uuuuuuuuuuuu+ NEW And the result according to the xfs_bmap_post_update trace was: 0 1 32 52 +H+wwwwwwwwwwwwwwwwwwwwwwww+ PREV Which is clearly wrong - it should be a merged unwritten extent, not an unwritten extent. That lead me to look at the LEFT_FILLING|RIGHT_FILLING|RIGHT_CONTIG case in xfs_bmap_add_extent_delay_real(), and sure enough, there's the bug. It takes the old delalloc extent (PREV) and adds the length of the RIGHT extent to it, takes the start block from NEW, removes the RIGHT extent and then updates PREV with the new extent. What it fails to do is update PREV.br_state. For delalloc, this is always XFS_EXT_NORM, while in this case we are converting the delayed allocation to unwritten, so it needs to be updated to XFS_EXT_UNWRITTEN. This LF|RF|RC case does not do this, and so the resultant extent is always written. And that's the bug I've been chasing for a week - a bmap btree bug, not a reflink/dedupe/copy_file_range bug, but a BMBT bug introduced with the recent in core extent tree scalability enhancements. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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#
# This list is used by git-shortlog to fix a few botched name translations
# in the git archive, either because the author's full name was messed up
# and/or not always written the same way, making contributions from the
# same person appearing not to be so or badly displayed.
#
# repo-abbrev: /pub/scm/linux/kernel/git/
#
Aaron Durbin <adurbin@google.com>
Adam Oldham <oldhamca@gmail.com>
Adam Radford <aradford@gmail.com>
Adrian Bunk <bunk@stusta.de>
Adriana Reus <adi.reus@gmail.com> <adriana.reus@intel.com>
Alan Cox <alan@lxorguk.ukuu.org.uk>
Alan Cox <root@hraefn.swansea.linux.org.uk>
Aleksey Gorelov <aleksey_gorelov@phoenix.com>
Aleksandar Markovic <aleksandar.markovic@mips.com> <aleksandar.markovic@imgtec.com>
Al Viro <viro@ftp.linux.org.uk>
Al Viro <viro@zenIV.linux.org.uk>
Andi Shyti <andi@etezian.org> <andi.shyti@samsung.com>
Andreas Herrmann <aherrman@de.ibm.com>
Andrey Ryabinin <ryabinin.a.a@gmail.com> <a.ryabinin@samsung.com>
Andrew Morton <akpm@linux-foundation.org>
Andrew Vasquez <andrew.vasquez@qlogic.com>
Andy Adamson <andros@citi.umich.edu>
Antoine Tenart <antoine.tenart@free-electrons.com>
Antonio Ospite <ao2@ao2.it> <ao2@amarulasolutions.com>
Archit Taneja <archit@ti.com>
Arnaud Patard <arnaud.patard@rtp-net.org>
Arnd Bergmann <arnd@arndb.de>
Axel Dyks <xl@xlsigned.net>
Axel Lin <axel.lin@gmail.com>
Bart Van Assche <bvanassche@acm.org> <bart.vanassche@wdc.com>
Bart Van Assche <bvanassche@acm.org> <bart.vanassche@sandisk.com>
Ben Gardner <bgardner@wabtec.com>
Ben M Cahill <ben.m.cahill@intel.com>
Björn Steinbrink <B.Steinbrink@gmx.de>
Boris Brezillon <boris.brezillon@bootlin.com> <boris.brezillon@free-electrons.com>
Boris Brezillon <boris.brezillon@bootlin.com> <b.brezillon.dev@gmail.com>
Boris Brezillon <boris.brezillon@bootlin.com> <b.brezillon@overkiz.com>
Brian Avery <b.avery@hp.com>
Brian King <brking@us.ibm.com>
Christoph Hellwig <hch@lst.de>
Christophe Ricard <christophe.ricard@gmail.com>
Corey Minyard <minyard@acm.org>
Damian Hobson-Garcia <dhobsong@igel.co.jp>
David Brownell <david-b@pacbell.net>
David Woodhouse <dwmw2@shinybook.infradead.org>
Deng-Cheng Zhu <dengcheng.zhu@mips.com> <dengcheng.zhu@imgtec.com>
Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Domen Puncer <domen@coderock.org>
Douglas Gilbert <dougg@torque.net>
Ed L. Cashin <ecashin@coraid.com>
Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Felipe W Damasio <felipewd@terra.com.br>
Felix Kuhling <fxkuehl@gmx.de>
Felix Moeller <felix@derklecks.de>
Filipe Lautert <filipe@icewall.org>
Franck Bui-Huu <vagabon.xyz@gmail.com>
Frank Rowand <frowand.list@gmail.com> <frowand@mvista.com>
Frank Rowand <frowand.list@gmail.com> <frank.rowand@am.sony.com>
Frank Rowand <frowand.list@gmail.com> <frank.rowand@sonymobile.com>
Frank Zago <fzago@systemfabricworks.com>
Greg Kroah-Hartman <greg@echidna.(none)>
Greg Kroah-Hartman <gregkh@suse.de>
Greg Kroah-Hartman <greg@kroah.com>
Gregory CLEMENT <gregory.clement@bootlin.com> <gregory.clement@free-electrons.com>
Henk Vergonet <Henk.Vergonet@gmail.com>
Henrik Kretzschmar <henne@nachtwindheim.de>
Henrik Rydberg <rydberg@bitmath.org>
Herbert Xu <herbert@gondor.apana.org.au>
Jacob Shin <Jacob.Shin@amd.com>
James Bottomley <jejb@mulgrave.(none)>
James Bottomley <jejb@titanic.il.steeleye.com>
James E Wilson <wilson@specifix.com>
James Hogan <jhogan@kernel.org> <james.hogan@imgtec.com>
James Hogan <jhogan@kernel.org> <james@albanarts.com>
James Ketrenos <jketreno@io.(none)>
Jason Gunthorpe <jgg@ziepe.ca> <jgg@mellanox.com>
Jason Gunthorpe <jgg@ziepe.ca> <jgunthorpe@obsidianresearch.com>
Javi Merino <javi.merino@kernel.org> <javi.merino@arm.com>
<javier@osg.samsung.com> <javier.martinez@collabora.co.uk>
Jean Tourrilhes <jt@hpl.hp.com>
Jeff Garzik <jgarzik@pretzel.yyz.us>
Jeff Layton <jlayton@kernel.org> <jlayton@redhat.com>
Jeff Layton <jlayton@kernel.org> <jlayton@poochiereds.net>
Jeff Layton <jlayton@kernel.org> <jlayton@primarydata.com>
Jens Axboe <axboe@suse.de>
Jens Osterkamp <Jens.Osterkamp@de.ibm.com>
Johan Hovold <johan@kernel.org> <jhovold@gmail.com>
Johan Hovold <johan@kernel.org> <johan@hovoldconsulting.com>
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
John Stultz <johnstul@us.ibm.com>
<josh@joshtriplett.org> <josh@freedesktop.org>
<josh@joshtriplett.org> <josh@kernel.org>
<josh@joshtriplett.org> <josht@linux.vnet.ibm.com>
<josh@joshtriplett.org> <josht@us.ibm.com>
<josh@joshtriplett.org> <josht@vnet.ibm.com>
Juha Yrjola <at solidboot.com>
Juha Yrjola <juha.yrjola@nokia.com>
Juha Yrjola <juha.yrjola@solidboot.com>
Kay Sievers <kay.sievers@vrfy.org>
Kenneth W Chen <kenneth.w.chen@intel.com>
Konstantin Khlebnikov <koct9i@gmail.com> <k.khlebnikov@samsung.com>
Koushik <raghavendra.koushik@neterion.com>
Krzysztof Kozlowski <krzk@kernel.org> <k.kozlowski@samsung.com>
Krzysztof Kozlowski <krzk@kernel.org> <k.kozlowski.k@gmail.com>
Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Leon Romanovsky <leon@kernel.org> <leon@leon.nu>
Leon Romanovsky <leon@kernel.org> <leonro@mellanox.com>
Leonid I Ananiev <leonid.i.ananiev@intel.com>
Linas Vepstas <linas@austin.ibm.com>
Linus Lüssing <linus.luessing@c0d3.blue> <linus.luessing@web.de>
Linus Lüssing <linus.luessing@c0d3.blue> <linus.luessing@ascom.ch>
Maciej W. Rozycki <macro@mips.com> <macro@imgtec.com>
Marcin Nowakowski <marcin.nowakowski@mips.com> <marcin.nowakowski@imgtec.com>
Mark Brown <broonie@sirena.org.uk>
Mark Yao <markyao0591@gmail.com> <mark.yao@rock-chips.com>
Martin Kepplinger <martink@posteo.de> <martin.kepplinger@theobroma-systems.com>
Martin Kepplinger <martink@posteo.de> <martin.kepplinger@ginzinger.com>
Matthew Wilcox <willy@infradead.org> <matthew.r.wilcox@intel.com>
Matthew Wilcox <willy@infradead.org> <matthew@wil.cx>
Matthew Wilcox <willy@infradead.org> <mawilcox@linuxonhyperv.com>
Matthew Wilcox <willy@infradead.org> <mawilcox@microsoft.com>
Matthew Wilcox <willy@infradead.org> <willy@debian.org>
Matthew Wilcox <willy@infradead.org> <willy@linux.intel.com>
Matthew Wilcox <willy@infradead.org> <willy@parisc-linux.org>
Matthieu CASTET <castet.matthieu@free.fr>
Mauro Carvalho Chehab <mchehab@kernel.org> <mchehab@brturbo.com.br>
Mauro Carvalho Chehab <mchehab@kernel.org> <maurochehab@gmail.com>
Mauro Carvalho Chehab <mchehab@kernel.org> <mchehab@infradead.org>
Mauro Carvalho Chehab <mchehab@kernel.org> <mchehab@redhat.com>
Mauro Carvalho Chehab <mchehab@kernel.org> <m.chehab@samsung.com>
Mauro Carvalho Chehab <mchehab@kernel.org> <mchehab@osg.samsung.com>
Mauro Carvalho Chehab <mchehab@kernel.org> <mchehab@s-opensource.com>
Matt Ranostay <mranostay@gmail.com> Matthew Ranostay <mranostay@embeddedalley.com>
Matt Ranostay <mranostay@gmail.com> <matt.ranostay@intel.com>
Matt Ranostay <matt.ranostay@konsulko.com> <matt@ranostay.consulting>
Matt Redfearn <matt.redfearn@mips.com> <matt.redfearn@imgtec.com>
Mayuresh Janorkar <mayur@ti.com>
Michael Buesch <m@bues.ch>
Michel Dänzer <michel@tungstengraphics.com>
Miodrag Dinic <miodrag.dinic@mips.com> <miodrag.dinic@imgtec.com>
Miquel Raynal <miquel.raynal@bootlin.com> <miquel.raynal@free-electrons.com>
Mitesh shah <mshah@teja.com>
Mohit Kumar <mohit.kumar@st.com> <mohit.kumar.dhaka@gmail.com>
Morten Welinder <terra@gnome.org>
Morten Welinder <welinder@anemone.rentec.com>
Morten Welinder <welinder@darter.rentec.com>
Morten Welinder <welinder@troll.com>
Mythri P K <mythripk@ti.com>
Nguyen Anh Quynh <aquynh@gmail.com>
Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Patrick Mochel <mochel@digitalimplant.org>
Paul Burton <paul.burton@mips.com> <paul.burton@imgtec.com>
Peter A Jonsson <pj@ludd.ltu.se>
Peter Oruba <peter@oruba.de>
Peter Oruba <peter.oruba@amd.com>
Pratyush Anand <pratyush.anand@gmail.com> <pratyush.anand@st.com>
Praveen BP <praveenbp@ti.com>
Qais Yousef <qsyousef@gmail.com> <qais.yousef@imgtec.com>
Oleksij Rempel <linux@rempel-privat.de> <bug-track@fisher-privat.net>
Oleksij Rempel <linux@rempel-privat.de> <external.Oleksij.Rempel@de.bosch.com>
Oleksij Rempel <linux@rempel-privat.de> <fixed-term.Oleksij.Rempel@de.bosch.com>
Oleksij Rempel <linux@rempel-privat.de> <o.rempel@pengutronix.de>
Oleksij Rempel <linux@rempel-privat.de> <ore@pengutronix.de>
Rajesh Shah <rajesh.shah@intel.com>
Ralf Baechle <ralf@linux-mips.org>
Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
Randy Dunlap <rdunlap@infradead.org> <rdunlap@xenotime.net>
Rémi Denis-Courmont <rdenis@simphalempin.com>
Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Ross Zwisler <zwisler@kernel.org> <ross.zwisler@linux.intel.com>
Rudolf Marek <R.Marek@sh.cvut.cz>
Rui Saraiva <rmps@joel.ist.utl.pt>
Sachin P Sant <ssant@in.ibm.com>
Sarangdhar Joshi <spjoshi@codeaurora.org>
Sam Ravnborg <sam@mars.ravnborg.org>
Santosh Shilimkar <ssantosh@kernel.org>
Santosh Shilimkar <santosh.shilimkar@oracle.org>
Sascha Hauer <s.hauer@pengutronix.de>
S.Çağlar Onur <caglar@pardus.org.tr>
Sebastian Reichel <sre@kernel.org> <sre@debian.org>
Sebastian Reichel <sre@kernel.org> <sebastian.reichel@collabora.co.uk>
Shiraz Hashim <shiraz.linux.kernel@gmail.com> <shiraz.hashim@st.com>
Shuah Khan <shuah@kernel.org> <shuahkhan@gmail.com>
Shuah Khan <shuah@kernel.org> <shuah.khan@hp.com>
Shuah Khan <shuah@kernel.org> <shuahkh@osg.samsung.com>
Shuah Khan <shuah@kernel.org> <shuah.kh@samsung.com>
Simon Kelley <simon@thekelleys.org.uk>
Stéphane Witzmann <stephane.witzmann@ubpmes.univ-bpclermont.fr>
Stephen Hemminger <shemminger@osdl.org>
Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Subhash Jadavani <subhashj@codeaurora.org>
Sudeep Holla <sudeep.holla@arm.com> Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com>
Sumit Semwal <sumit.semwal@ti.com>
Tejun Heo <htejun@gmail.com>
Thomas Graf <tgraf@suug.ch>
Thomas Pedersen <twp@codeaurora.org>
Tony Luck <tony.luck@intel.com>
Tsuneo Yoshioka <Tsuneo.Yoshioka@f-secure.com>
Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de>
Uwe Kleine-König <ukl@pengutronix.de>
Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Vinod Koul <vkoul@kernel.org> <vinod.koul@intel.com>
Vinod Koul <vkoul@kernel.org> <vinod.koul@linux.intel.com>
Vinod Koul <vkoul@kernel.org> <vkoul@infradead.org>
Viresh Kumar <vireshk@kernel.org> <viresh.kumar@st.com>
Viresh Kumar <vireshk@kernel.org> <viresh.linux@gmail.com>
Viresh Kumar <vireshk@kernel.org> <viresh.kumar2@arm.com>
Vlad Dogaru <ddvlad@gmail.com> <vlad.dogaru@intel.com>
Vladimir Davydov <vdavydov.dev@gmail.com> <vdavydov@virtuozzo.com>
Vladimir Davydov <vdavydov.dev@gmail.com> <vdavydov@parallels.com>
Takashi YOSHII <takashi.yoshii.zj@renesas.com>
Yakir Yang <kuankuan.y@gmail.com> <ykk@rock-chips.com>
Yusuke Goda <goda.yusuke@renesas.com>
Gustavo Padovan <gustavo@las.ic.unicamp.br>
Gustavo Padovan <padovan@profusion.mobi>
Computing file changes ...
